Aircraft passengers have an expectation that they will be able to use their Portable Electronic Devices (PEDs) during flight. Some examples of PEDs include smart phones, tablets, portable computers, etc. Passengers may utilize their PEDs to access the various In-Flight Entertainment (IFE) options (e.g., movies, television shows, music, the Internet, etc.) that may be provided by an aircraft data network.
PEDs interface with the aircraft data network using a Wireless Local Area Network (WLAN). One example of a WLAN includes Wi-Fi. Wi-Fi commonly utilizes channels in the 2.4 GigaHertz (GHz) frequency band and/or in the 5 GHz frequency band. 2.4 GHz Wi-Fi provides a 20 MegaHertz (MHz) bandwidth per channel, with 11 total channels available worldwide due to per-country limitations. 5 GHz Wi-Fi provides a 20 MHz, 40 MHz, 80 MHz, or 160 MHz bandwidth per channel, with 18 total channels available (mostly) worldwide due to per-country limitations.
Since WLANs depend upon the use of a limited radio bandwidth across a finite number of possible channels, the possibility exists onboard the aircraft that bandwidth limitations will result in a poor quality of service for the passengers. For example, a wide body aircraft such as the 777 may have more than 400 passengers, with each passenger possibly having a PED in use for accessing the IFE options onboard the aircraft. To stream a movie or television show at 1080p, a WLAN implementation may be tasked with transporting about 5-6 million bits per second (Mbps) for each stream, depending on the codec that is in use (e.g., H.264 in this example). Multiplied across the number of passengers in the aircraft, the 2 billion bits per second (Gbps) data rate across the WLAN implementation on the 777 may be impractical. This process is aggravated at even higher resolutions streams. At quad-HD (4K streams), the per stream data rate increases to 18-20 Mbps, depending on the codec that is in use (e.g., H.264 in this example). Multiplied across the number of passengers in the aircraft, the 7.2 Gbps data rate across the WLAN implementation on the 777 is likely to be even more impractical.
Although new codecs may be capable of reducing the WLAN data rate requirements (e.g., H.265 may be capable of reducing the WLAN data rate by as much as 50%), even this reduction may be insufficient to overcome the inherent bandwidth and channel limitations that are present in aircraft WLAN implementations.
Thus, present aircraft WLAN implementations may be inadequate to provide the quality of service that aircraft passengers have come to expect onboard the aircraft for IFE content delivery.